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Equilibrium sampling through membranes of freely dissolved chlorophenols in water samples with hollow fiber supported liquid membrane

Liu, Jing-fu LU ; Jönsson, Jan Åke LU and Mayer, P (2005) In Analytical Chemistry 77(15). p.4800-4809
Abstract
The freely dissolved concentration (C-free) of pollutants is generally believed to be bioavailable and thus responsible for toxic effects. The C-free of organic weak acids and bases consists of a dissociated and a nondissociated fraction. By using chlorophenols as model compounds, a negligible-depletion extraction technique, equilibrium sampling through membranes (ESTM), was developed for the measurement of the nondissociated part of the C-free. Polypropylene hollow fiber membranes (280-mu m i.d., 50-mu m wall thickness, 0.1-mu m pore size, 15-cm length) were impregnated with undecane in the pores in the fiber wall as liquid membrane and filled with buffer solution in the lumen as acceptor. Then, the hollow fiber membranes were placed into... (More)
The freely dissolved concentration (C-free) of pollutants is generally believed to be bioavailable and thus responsible for toxic effects. The C-free of organic weak acids and bases consists of a dissociated and a nondissociated fraction. By using chlorophenols as model compounds, a negligible-depletion extraction technique, equilibrium sampling through membranes (ESTM), was developed for the measurement of the nondissociated part of the C-free. Polypropylene hollow fiber membranes (280-mu m i.d., 50-mu m wall thickness, 0.1-mu m pore size, 15-cm length) were impregnated with undecane in the pores in the fiber wall as liquid membrane and filled with buffer solution in the lumen as acceptor. Then, the hollow fiber membranes were placed into the sample (donor) for an equilibrium extraction after sealing the two ends. The chlorophenol concentrations in the acceptor were then determined by direct injection into a HPLC system. Finally, the C-free Of the nondissociated and the dissociated species of a chlorophenol were calculated based on its measured concentration in the acceptor, its pK(a) value, and the measured pH in sample and acceptor. Theoretically calculated distribution coefficients (D = 8-970) agree well with the experimental enrichment factors (E-e(max) = 6-1124), and the equilibration time was observed to increase with increasing distribution coefficients (hours to days). The freely dissolved concentration of five chlorophenols, with a wide range of pKa (4.9-9.2) and log K-OW (2.35-5.24), were successfully determined in model solutions of humic acids and at low-ppb levels in river and leachate water. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Analytical Chemistry
volume
77
issue
15
pages
4800 - 4809
publisher
The American Chemical Society
external identifiers
  • wos:000230920600025
  • scopus:23044449478
ISSN
1520-6882
DOI
10.1021/ac0503512
language
English
LU publication?
yes
id
6f56dced-c36f-42d4-a9e0-a676f3fb915e (old id 150984)
date added to LUP
2007-06-27 10:26:52
date last changed
2017-07-02 03:47:35
@article{6f56dced-c36f-42d4-a9e0-a676f3fb915e,
  abstract     = {The freely dissolved concentration (C-free) of pollutants is generally believed to be bioavailable and thus responsible for toxic effects. The C-free of organic weak acids and bases consists of a dissociated and a nondissociated fraction. By using chlorophenols as model compounds, a negligible-depletion extraction technique, equilibrium sampling through membranes (ESTM), was developed for the measurement of the nondissociated part of the C-free. Polypropylene hollow fiber membranes (280-mu m i.d., 50-mu m wall thickness, 0.1-mu m pore size, 15-cm length) were impregnated with undecane in the pores in the fiber wall as liquid membrane and filled with buffer solution in the lumen as acceptor. Then, the hollow fiber membranes were placed into the sample (donor) for an equilibrium extraction after sealing the two ends. The chlorophenol concentrations in the acceptor were then determined by direct injection into a HPLC system. Finally, the C-free Of the nondissociated and the dissociated species of a chlorophenol were calculated based on its measured concentration in the acceptor, its pK(a) value, and the measured pH in sample and acceptor. Theoretically calculated distribution coefficients (D = 8-970) agree well with the experimental enrichment factors (E-e(max) = 6-1124), and the equilibration time was observed to increase with increasing distribution coefficients (hours to days). The freely dissolved concentration of five chlorophenols, with a wide range of pKa (4.9-9.2) and log K-OW (2.35-5.24), were successfully determined in model solutions of humic acids and at low-ppb levels in river and leachate water.},
  author       = {Liu, Jing-fu and Jönsson, Jan Åke and Mayer, P},
  issn         = {1520-6882},
  language     = {eng},
  number       = {15},
  pages        = {4800--4809},
  publisher    = {The American Chemical Society},
  series       = {Analytical Chemistry},
  title        = {Equilibrium sampling through membranes of freely dissolved chlorophenols in water samples with hollow fiber supported liquid membrane},
  url          = {http://dx.doi.org/10.1021/ac0503512},
  volume       = {77},
  year         = {2005},
}